Look at the controls on this e-reader
The function of any device is to do something. (of + to)
The function of the power button is to turn the computer off/on.
A device is used for doing something. (-ing form)
An e-reader is used for reading e-books.
A device enables the user to do something (the user + to)
A printer enables the user to print a document.
Complete these sentences:
1) The function of the
is to turn the page.
2) The
is used for adjusting the brightness.
3) The
enables (allows) the user to adjust the font size.
